There is an increasing public awareness of the presence of potentially harmful materials of a microscopic size. These materials may include, for example, lead dust generated by the deterioration of lead paint, asbestos fibers which can become airborne if disturbed, biohazards which can be produced during medical treatment of infectious disease patients and allergenic debris caused by organic dusts, pollens and microscopic biological materials (such as dust mites).
During the last 18 months there have been a number of dramatic developments relating to lead. The U.S. Environmental Protection Agency (EPA) has announced that lead poisoning is the single greatest environmental health threat faced by children in America. In addition, the Center for Disease Control in Atlanta, Ga., recently issued a national health bulletin reducing the levels of lead in the blood considered to officially constitute "poisoning." The new levels are 1/10the of the old standards. New medical data indicates that neurological damage (particularly in children) can be caused by much smaller amounts of lead in the blood than was previously known.
The EPA and other health authorities have determined that the most common source of lead ingestion in children is dust. The widely publicized lead paint "chips" which are eaten by children are usually only found in seriously deteriorating structures. Lead paint dust, on the other hand, is found everywhere there is lead paint because lead paint naturally forms a light surface patina of lead-containing dust as it ages. This dust sluffs off and falls onto rugs, furniture and other surfaces. Lead dust hazards are increased by normal home renovation and maintenance activities which disturb lead-contaminating dust.
With respect to asbestos contaminated particulate, this particulate is primarily produced from asbestos used as a heat insulating, fireproof material. Asbestos use was extensive in all fields of construction prior to the recent concern about the health hazards involved with the use of asbestos. With the recent public awareness of the detrimental effects of the exposure to asbestos found in airborne dust and the like, many clean-up campaigns have been undertaken to eliminate asbestos and asbestos-containing dust from public places. Asbestos-containing dust has therefore now also become a major health concern.
Asbestos-containing particles and dust are generated during the removal of asbestos, routine building renovations and building maintenance. In addition, asbestos-containing materials have been found to regularly sluff off from pipe and boiler covering materials, ceiling coverings, and insulation during normal wear and tear of the asbestos-containing insulation and materials. Particular attention has now been given to this problem in schools and other public buildings where accumulations of asbestos-containing dust is commonly found in corridors, rooms and maintenance areas.
The clean up of asbestos-containing dust as well as other harmful contaminants, is a problem unto itself. The fine asbestos particles found in asbestos-containing dust present asbestos in its most dangerous form. Asbestos fibers in dust easily take flight on air currents and can readily circulate throughout an entire air circulation system of a building. The levels of contamination, though invisible to the human eye, are often as high as those levels of contamination which have been documented to cause significant percentages of cancer in exposed populations.
Present practice for the removal of asbestos-containing dust includes the use of industrial machines for the removal of toxic dust. These machines are large, heavy-duty vacuum cleaners, specially designed for this purpose. The vacuum cleaners are equipped with special internal HEPA filtration systems. They operate by placement of a vacuum cleaner hose adjacent to asbestos-containing dust and creating a vacuum to suck in dust through the hose. The air suction of the vacuum cleaner through the hose draws dust into the unit where large debris is trapped in coarse, disposable filter bags. Exhausted air is then forced through thick HEPA filtration material, which traps the sub-micron sized fibers. The air exiting the unit is clear of toxic material.
A serious unpublicized, but widely-recognized problem, associated with even sophisticated HEPA vacuum cleaners is that these machines must be emptied when they become full with asbestos-containing debris. The only method for emptying these machines is to open the machine, take out the bag of collected asbestos debris and dispose of the contaminated bag. This process creates substantial amounts of airborne contamination in the surrounding environment and is quite hazardous to an unprotected operator.
Another attempt to remove asbestos-containing dust includes the use of standard vacuum cleaners which are, in effect, asbestos recontamination machines since they contain no HEPA filter or other asbestos decontamination mechanism. Asbestos-containing dust is drawn into a non-HEPA filtered vacuum cleaner, trapping the debris in a disposable debris bag. The air exhausted from the machine is filled with asbestos fibers and is circulated into the surrounding environment by the force of the exhausted air.
U.S. Pat. No. 4,072,483 to Doyle, Jr., discloses a vacuum cleaner employing a plurality of filters for picking up asbestos fibers. When it is desired to dispose of the asbestos fibers, the cover of the vacuum cleaner is opened and the filters are manually pulled from the tank, exposing the operator to asbestos contamination.
U.S. Pat. No. 4,229,193 to Miller, discloses a filter bag for a vacuum cleaner. The filter bag includes a primary filter bag, an impermeable shield and a secondary filter as a single unit. The filters are encapsulated within the impermeable shield. The area of the impermeable shield, which surrounds the opening into the primary filter bag, has an opening therethrough which is aligned with and is the same size as an opening of a container through which a hose connection with the container is made. The opening communicates through the impermeable shield and through the inlet of the primary filter bag, into the interior of the filter bag. To dispose of the filter bag, the bag must be removed from the vacuum cleaner.
U.S. Pat. Nos. 4,613,348 and 4,726,825 to Natale disclose a plastic disposable canister containing a HEPA filtration mechanism. Once full with asbestos-containing dust, the entire canister including the HEPA filtration mechanism is disposed of following proper disposal procedures for asbestos.
A problem, not specifically addressed by the prior art practices, is the increasingly stringent guidelines governing the collection and removal of lead-contaminated particulate during demolition, renovation, and normal wear and tear. It has been determined that the fine particles of lead, which can become airborne during renovation or demolition, pose a hazardous situation at least equally as dangerous to the public health as was determined to exist by exposure to asbestos-containing dust. No steps have presently been taken to address this potentially serious problem.